1. No he flat out said "she doesn't want to be yours" there really is no other way to take that than "she has no interest being in a relationship with you"
2. because Kakashi was there when Sakrua said she didn't want to pursue a relationship with Sasuke anymore in the Land of iron
3. Because we have people here who can actually translate, words that kakashi used were in the context "used to love", "someone you liked".
1. Did he say "she never wants to be yours"? Sakura wanting to be in a relationship with current crazy Sasuke would be kittened up, her main priority is saving him, as kittened up as it is Kakashi is probably just pointing out how unconditional her love is. Actually the fact that she is so focused around Sasuke is in itself very alarming.
2. Which chapter was that?
3. I checked and no it's either past progressive or present perfect and it's only said once.